1. Field of the Invention
The present invention relates to an integrated circuit package cooling mechanism used in electronic devices such as information processors, and particularly relates to a cooling device in an integrated circuit package comprising a plurality of integrated circuit chips disposed on a printed wiring board to make a matrix.
2. Description of the Prior Art
An example of a conventional integrated circuit package cooling mechanism of this type is shown in FIG. 6. This is cited from "A Conduction-Cooled Module for High-Performance LSI Devices" by S. Oktay and H.C. Kammerer (IBM J/RES. DEVELOP. vol. 26, No. 1, Jan. 1982). In FIG. 6, a wiring substrate 161 is provided with an integrated circuit chip 162 mounted thereon, and a spring 163 presses a piston 164 against the chip so that the heat at the chip is transferred to a cooling plate 168 through a space filled with helium gas 165 and via a hat 166 and an intervening layer 167, and then discharged to a liquid coolant 169 circulating in the cooling plate 168. The reference numeral 170 indicates an I/O pin of the wiring substrate 161. Including this one, several cooling devices have been invented and put into practice.
The Japanese Patent Application Laid-open No. 60150/85 discloses a cooling device using impinging jet of liquid coolant. FIG. 7 shows the configuration of such a cooling device.
As shown in FIG. 7, this cooling device transfers the heat generated at a chip 232 mounted on a printed wiring board 231 to a heat transfer plate 235 via a heat transfer board 233 and a variable heat transfer substance 234, and cools down the heat transfer plate 235 by jet of the liquid coolant from a nozzle 236. The heat transfer plate 235 is pressed against the chip 232 by a bellows 238 fixed to a cooling header 237 via the variable heat transfer substance 234 and the heat transfer board 233.
Among conventional cooling mechanisms described above, the one shown in FIG. 6 has a coolant channel in its cooler plate designed for heat transfer by forced convection, but the heat transfer ratio obtained by this mechanism is about 0.1 to 0.5 W/cm.sup.2 .degree. C. at most. This is not sufficient cooling capacity for an integrated circuit chip with higher integration. The mechanism in FIG. 7 can achieve a higher heat transfer ratio, but its thin bellows is susceptible to corrosive holes under the affect of liquid coolant, which may result in leakage of coolant.